What was Russell Brand up to while Katy Perry prepared for her blistering kiss-off performance of "Part of Me" at the Grammys? According to the London Sun, he was adding another notch to his once notoriously whittled-away headboard.

Over the weekend, the British tab spied the scruffy, leg warmer-clad funnyman kissing a mystery brunette goodbye. Seems he was dropping her off at her Los Angeles apartment following an apparent overnight visit to his bachelor pad (she was clad in towering platforms and a dressy ensemble more appropriate for night than day).

"Russell is a single man again and starting to move on from Katy," explains a source. "Like any bloke, he had missed female company. He isn't quite back to his old ways yet, but he's very much back in the saddle."

But Brand might want to prepare for a bumpy ride, because Us Weekly says he can expect more musical disses from his estranged missus.

"She's writing songs now that chronicle their relationship," a source tells the mag. "She's turning her rage into creativity."

If you missed Katy's Grammy night number, her bitter ditty included such pointed lyrics as, "You chewed me up and spit me out, like I was poison in your mouth ... You can keep the diamond ring, it don't mean nothing anyway."

The insider adds that Katy "was worried" Russell might go after her millions in their prenup-free divorce, but "now she's great," which might explain why she signed their divorce documents with a smiley face.